1. Field
The present disclosure relates to a gait rehabilitation robot having a passive mechanism, and more particularly, to a gait rehabilitation robot having a component capable of relieving a force generated at a joint portion which prevent user's ankles from going through an excessive force.
2. Description of the Related Art
A gait rehabilitation robot is a device for assisting a patient, having a lower half paralysis or deterioration because of aging or muscle weakening, to perform gait training without giving an excessive force to the leg. The gait rehabilitation robot is classified into a type which is directly worn by a patient in any time from gait training to daily life and, also, into a type which can be installed at a treadmill so that a patient may repeatedly perform gait training.
FIGS. 1a and 1b are diagrams showing the change of angle occurring at the lower extremity when a pedestrian stops on the ground and is walking.
Referring to FIG. 1a, in the case a pedestrian stops on the ground, based on the pelvis, the lower extremity including the hip joint and the ankle joint is perpendicular to the ground.
Meanwhile, referring to FIG. 1b, in the case (of) a pedestrian is walking, the center of gravity shifts according to the movement of the pelvis, and at the lower extremity supported by the ground, particularly the hip joint and the ankle joint, angles α, β change due to extroversion/introversion and eversion/entropion.
If the change of angle occurs at the lower extremity as shown in FIG. 1b during the user's performance, a mechanism for compensating such change of angle should be implemented. If such a mechanism is not implemented, as shown in the enlarged portion of FIG. 1b, a rigid body in contact with the foot of the rehabilitating person is separated from the ground or the treadmill, and an excessive force is applied to the ankle joint and the hip joint. In other case, the foot of the rehabilitating person may be pulled along the shifting direction of the center of gravity.
In this regard, Korean Unexamined Patent Publication No. 2010-0044360 discloses a wheelchair-type gait assisting robot, in which the arm and the exoskeleton are integrally coupled without any need of separating, and an ankle driving device is located at the exoskeleton, instead of the arm, to prevent problems caused when the arm and the exoskeleton are separated. In addition, Korean Unexamined Patent Publication No. 2010-0106527 discloses a gait assisting device, which includes an exoskeleton, a power source configured as a battery pack or another similar embedded power pack, a power cable coupled thereto, and a control system.
In case of a general gait rehabilitation robot, a mechanism for compensating the change of angle of the lower extremity is absent or the lower extremity is vertically fixed on the ground, which disturbs natural gait training. In other words, since a general gait rehabilitation robot does not have a component for relieving a force caused by introversion and extroversion at an ankle portion, when a rehabilitating person performs rehabilitation training, an excessive force is applied to the ankle of the rehabilitating person.
Therefore, there is a demand for the development of a device capable of ensuring a user to stably perform gait training without applying an excessive force to an ankle of a rehabilitating person wearing the gait rehabilitation robot and performing gait training.